Coaxial cables are high-frequency electrical transmission lines commonly used in the cable television industry to carry high-frequency or broadband signals, such as cable TV signals to television sets. Coaxial cables typically consist of a round conducting wire (also referred to herein as the “inner conductor” or “center conductor”) surrounded by an insulating spacer or “dielectric” that may be solid or perforated with air spaces and may be covered with an aluminum foil. The insulating spacer is surrounded by a cylindrical conducting sheath (also referred to herein as the “outer conductor”), which is usually surrounded by a final (i.e., outer) insulating layer (referred to herein as the “jacket” or “sheath”). The jacket or sheath is typically made of a plastic material to insulate the cable and provide protection against corrosion and weathering. Coaxial cables are used as high-frequency transmission lines to carry a high-frequency or broadband signals. Because the electromagnetic field carrying the signal exists (ideally) only in the space between the inner and outer conductors, it cannot interfere with or suffer interference from external electromagnetic fields.
Coaxial cables are typically connected using RF (radio frequency) connectors, which are electrical connectors designed to work at radio frequencies in the multi-megahertz range. RF connectors are designed to maintain the shielding that the coaxial design offers. Higher quality versions also minimize the change in transmission line impedance at the connection. These connectors have a fastening mechanism (thread, bayonet, braces, push pull) and springs for a low ohmic electrical contact at a designed insertion force which allows multiple reconnects without reduced performance.
One type of connector used with coaxial cables includes a plastic sleeve that secures the cable in the connector. These connectors use a post barb to expand the cable and a plastic sleeve to secure the cable and provide both cable retention and a water tight seal around the cable jacket. This design works well for specific cable diameters that correspond to the inner diameter of the sleeve. However, if the inner diameter of the sleeve is increased so that the connector can also be used with cables having larger diameters, the cable retention level drops and the seal is lost when the connector is used with cables having smaller diameters. Therefore, there is a need for a coaxial cable connector with a sleeve that can accommodate cables of different diameters and still provide good cable retention and a good seal.